No it isn't a new discussion... there's virtually no topic that hasn't already been discussed ad nauseum around here, lol. But 99.97% of it boils down to personal preference. Perception is fickle, weird, mostly without a concrete explanation, and nearly impossible to duplicate from one person to the next. Nobody's "right", and there's no universal truth to be found. You'll either like an individual pair of headphones (or monitors, whatever), or you won't...and that's fine. But don't bother fixating on any one individual spec as a magic bullet...none of this stuff works that way. You could go out and spend $2K on some boutique mahogany shell 300 ohm headphones, hand crafted for the Sultan of Brunei, and end up hating them. My AKG 701's are all of 55 ohms, and I love the way they sound. All you can do is try stuff and see what you like.
Plus, if the same cans sound good through an interface but lousy directly from the Helix (or vice versa), or they sound great for 11 minutes every other Tuesday, then it's hard to blame the headphones... they're not changing from minute to the next. which means something else is going on.